The invention relates to a traffic monitoring device comprising:
a picture recording unit provided for recording a sequence of successive traffic pictures of a same traffic road;
a detection zone determination unit connected with the picture recording unit and provided for determining a traffic detection zone within the traffic pictures of said sequence;
a picture analysis unit provided for cooperating with the picture recording unit and the detection zone determination unit and for verifying from each time a supplied traffic picture if an object to be identified as a vehicle is present within said traffic detection zone.
The invention also relates to a method for monitoring the traffic present on a traffic road.
Such a traffic monitoring device is known and brought on the market by Wootton Jeffreys Consultants under the name Impacts. A picture recording unit, formed by a TV camera, records successive pictures of a traffic. Within each picture a detection zone is determined within which the traffic will be analyzed. The picture analysis unit checks the picture content of the detection zone in order to verify if, within the detection zone, an object to be identified as a vehicle is present. This enables monitoring the traffic in an electronic manner and verification for example, if a traffic jam occurs. The latter is realized by verifying how many objects identified as vehicle are present in the recorded picture.
With the known traffic monitoring device a rectangle is used as detection zone, which rectangle is superposed on the picture of the road to be monitored. In such a manner the traffic road is divided into multiple rectangles. The dimension of each rectangle is chosen in such a manner that a vehicle can easily fit therein. If the picture analysis unit now establishes that more than one vehicle is present within such a rectangle, the latter is indicated in the recorded picture by way of a change in the color of the rectangle contours, for example from blue to red. This indicates where a problem is present within the traffic.
A drawback of the known traffic monitoring device is that by using rectangles the picture analysis unit has to take into account a large number of pixels, for each picture more than 2,000 pixels are taken into account which requires a considerable calculation capacity. Besides and in order to obtain a reliable system, it is necessary, as traffic situation can rapidly change, to have the pictures from the sequence succeeding rapidly one to another. This again imposes a high demand on the calculation capacity of the device.
A further drawback of the know traffic monitoring device is that upon analyzing the subsequent pictures no correlation is established between those pictures.
It is an object of the invention to realize a traffic monitoring device wherein, without reducing the reliability of the device, a relatively reduced calculation capacity is enough for what concerns the picture analysis, and wherein also a correlation between successive pictures can be determined.